CN116171213A

CN116171213A - Method for producing an OSB or wafer plate, device for producing an OSB or wafer plate, and OSB or wafer plate

Info

Publication number: CN116171213A
Application number: CN202180061521.6A
Authority: CN
Inventors: S·齐默尔; P·J·贝克; U·凯泽
Original assignee: Siempelkamp Maschinen und Anlagenbau GmbH and Co KG
Current assignee: Siempelkamp Maschinen und Anlagenbau GmbH and Co KG
Priority date: 2020-09-09
Filing date: 2021-08-25
Publication date: 2023-05-26
Also published as: DE102020005512B4; WO2022053312A1; DE102020005512A1

Abstract

The invention relates to a method for producing OSB or waffle boards from wood chips with a length of 1 to 60mm, comprising the steps of a) comminuting wood into fines (12), ready-made material (11) and coarse material (13), wherein the ready-made material has at least a major part of the wood chips, b) sorting the fines, ready-made material and coarse material according to size, c) drying at least the ready-made material, d) gluing at least a part of the ready-made material, e) spreading at least the ready-made material into bulk material mats (9), and f) pressing the OSB or waffle boards (10) into bulk material mats. In order to make the manufacturing method for chipboards of the same quality or even higher quality more resource-efficient and less costly, it is provided that the wood used also comprises small-diameter wood with a diameter of less than 0.08m and that at least one arbor cutter is used for comminution.

Description

Method for producing an OSB or wafer plate, device for producing an OSB or wafer plate, and OSB or wafer plate

Technical Field

The invention relates to a method for manufacturing oriented strand board or wafer board from wood chips having a length of 35 to 180mm of at least more than 50% of the total mass, comprising the steps of,

a) Pulverizing wood into fine, useful and coarse materials, wherein the useful materials have at least a majority of wood chips,

b) Sorting the fine materials, the useful materials and the coarse materials according to the size,

c) At least the materials used for the production are dried,

d) At least a portion of the useful material is glued,

e) At least spread the useful material into a mat, and

f) The mat is pressed into oriented strand board or wafer board.

The invention further relates to an oriented strand board or wafer board manufactured according to the method according to the invention.

Background

There are a number of publications and patent applications concerning the manufacture of Oriented Strand Board (OSB) or waferplate (waferplate). Features a) to f) for producing OSB or wafer sheets are present in almost all production methods and can be used in part in different ways. The sequences a) to f) given may also be different. In particular, the sorting can also take place after drying or before and after drying.

The comminution of the wood to be used is usually carried out by first decorticating the trunk and subsequently producing wood chips of the above-mentioned board type from the decorticated wood using a ring-type direct cutter or a disk cutter. In both cases, the wood must be debarked in order to achieve an economical tool life. Based on the cutting machining method of the cutting machine described above, wood with a small diameter (< 100 mm) can only be used in small amounts or not at all, since otherwise small wood yields with a high fines ratio result. An alternative cutting process exists in which wood chips are produced in two stages, i.e. first wood chips are produced, which are broken into wood chips in a subsequent working step by means of a knife ring cutter. Disadvantageous in both processes is the high machine outlay, which leads to high investment costs and energy costs (space requirements, foundations, buildings, power consumption). Furthermore, the service life of the tools in a knife ring cutting machine is typically only a few hours, which results in frequent downtime maintenance.

The wood chips obtained are usually sorted after drying, for example in a drum dryer. For this purpose, for example, a disc screen is used. The material is divided into different chip parts. Different wood chip sizes are assigned to the following plies and are spread accordingly. For example, it can be provided that smaller wood chips are provided in the interior, the so-called middle layer, and larger wood chip sizes are provided in the exterior, the cover layer. Thus, the OSB or wafer plate obtains a relatively high flexural strength.

Disclosure of Invention

The object of the present invention is therefore to design a manufacturing process for particle boards of the same quality or even higher quality in a resource-saving and cost-effective manner. The significance of the method is mainly reflected in mechanical characteristics, in particular to bending strength, screw tensile strength and elastic modulus.

With respect to the manufacturing method, this object is achieved by the features of claim 1 and in particular by the fact that the wood used also comprises small-diameter wood with a diameter of less than 0.08m and that at least one arbor cutter is used for the comminution.

The inventors have recognized that small diameter wood can also be fully used to produce high quality OSB or waffle boards if an arbor cutter is used instead of a chopper and knife ring cutter for shredding. In the case of arbor cutters, space requirements and maintenance costs are significantly lower. The new embodiment brings about a great difference, requiring only about half the energy consumption required for cutting with a chopper and knife ring cutter, and in practice only one tenth of the space requirement.

Arbor cutters also allow smaller trunk diameters to be cut. Barked wood, which is generally well above 0.08m in trunk diameter, can only be handled to an unsatisfactory extent with knife ring cutters. Here, the diameter is defined as dividing the circumference by the number Pi (pi=3.14). So-called chips are often generated when using arbor cutters. Chips are wood cutting residues that are difficult to classify using conventional screening techniques. Fragments can partially enter the press and cause damage especially in continuous presses. The chips also reduce the quality and appearance of the OSB or wafer sheet produced.

However, the increase in the possibility of using so-called small diameter wood or industrial waste wood with a diameter of less than 0.08m is also significantly more cost-effective, since these types of wood are lower in purchasing costs. Even wood with a diameter of from 0.04m was tested with positive results.

Preferably, the proportion of wood chips made of small diameter wood in the OSB or wafer plate is at least 30%, preferably at least 50%.

From this size class, the manufacturing process becomes particularly economical. The total proportion of wood chips used in the arbor cutters for OSB or wafer boards should be 30% to 100%. Of course, a plurality of arbor cutters may be employed. For example, it is also interesting in many cases to use two differently arranged arbor cutters, one of which produces wood chips for the intermediate layer and the other for the cover layer.

In particular, it is advantageously provided that unpeeled wood is also used as wood.

Here, too, an advantageous use of the arbor cutting machine can be seen, which is capable of better cutting unpeeled wood into high quality wood chips, in particular in such a way that bark parts can be introduced into OSB or wafer plates or easily sorted in a manner explained later.

Preferably the arbor cutter produces wood chips having a thickness of 0.1 to 0.8 mm.

The shape of the wood chips is very important for the quality of the OSB or wafer plate later. It affects the amount of glue used, the specific gravity and the mechanical properties. Therefore, it is possible to manufacture high quality wood chips from small diameter wood or industrial waste wood using the arbor cutter because the arbor cutter is more likely to produce a very flat sheet. These sheets have a higher slenderness (ratio of chip length to chip thickness), are more easily wetted with glue and form a strong bond.

This is also considered to be the reason why processing in this way is preferred, i.e. to achieve a flexural strength corresponding to the value of EN 300.

However, this is the case, with the screening techniques most often used conventionally, only chip, bark and other coarse materials can be sorted to a limited extent. It is therefore proposed by the inventors, optionally but in an advantageous manner, to sort at least partly with a trommel or star screen. It has surprisingly been found that trommels can sort chips, bark and other coarse materials.

For example, a trommel screen is available in DE3836608A1 and a star screen is available in DE4415815 A1. However, the screen device arranged downstream of the comminution device is preferably arranged as a drum screen fed from the inside, which has already been tested in the test, in particular should be cleaned with a rotating brush. It may constitute, for example, 30% to 70% of the length of the cylinder. The drum conveying the shredded material is preferably slightly inclined in the direction of feed-through. The drum has a drum inner wall configured as a screen.

It is particularly advantageous if the mesh size of the screen is larger in the direction of travel, so that the fine material is discharged from the drum first, the material is discharged at a next position in the direction of travel, and the coarse material is discharged at the rear end in the direction of passage, and is preferably removed before the glue is applied.

In an alternative or additional preferred embodiment of the invention, the sorting (preferably with a trommel or star screen) is already carried out before the drying.

The skilled person distinguishes between "wet zones" in which the percentage of the water mass contained in the wood to the dry mass of the wood, i.e. the wood moisture, is about 60% to 180%, and "dry zones" in which the wood moisture is typically 1.5% to 10%, according to the degree of dryness. In the known devices of the prior art, the sorting is always carried out in the drying zone. However, the inventors have recognized advantages associated with wet differentiation because the energy consumption is significantly reduced in wet differentiation.

Preferably, the useful material and possibly fines for the different OSB or wafer plies are separated again and transported to different silos. From these bins the chips are led on to the respective spreading heads assigned to the cover layer and the intermediate layer. Of course, the wood chips must be glued before being spread.

Advantageously, the wood chips are arranged to pass through a hot air separator before being dried.

Such a hot air separator is shaped, for example, like an omega. The useful material is then guided through the omega-shaped tubes with hot air and pre-dried on the one hand before the material is guided to the actual drying process, which takes place for example in a drying drum. Second, heavy coarse particles not carried by the air stream are guided out through the discharge port based on gravity before reaching the apex of the omega-shaped tube. The hot air may be generated, for example, by combustion of wood dust particles generated in the process. There is also a high outlay and energy saving space with this measure.

The bark parts remaining in the wood chips are preferably separated during the spreading in such a way that they are spread in the middle region, seen in the thickness of the OSB or wafer plate.

By this measure, the bark separation process is additionally advantageously utilized. The bark material which is disadvantageously deposited on the surface of the OSB or wafer plate is not derived in advance, but is first separated by a separation process during the spreading process and then spread by the spreading device in the intermediate layer of the bulk mat to be pressed for the OSB or wafer plate. Whereby bark parts are invisible hidden in the OSB or wafer plate.

Furthermore, an apparatus for producing OSB or wafer sheets, which operates according to the method, should be protected.

Furthermore, OSB or wafer plates should be protected, which can be produced according to the method according to one of claims 1 to 13.

Drawings

The invention is further explained below with the aid of the figures which show embodiments. In the drawings:

fig. 1 is a flow chart of a method according to the invention.

Detailed Description

In fig. 1, an embodiment of the invention is shown by an exemplary flow chart of a manufacturing method for particle boards according to the invention. The device components essential to the process are shown in seven boxes. For most cases, the sequence shown is also the procedure followed when using the equipment unit. However, minor variations of this order or the addition of other equipment units are possible and should not limit the inventive concept.

A arbor cutter (messerwellenzerstier) 1 is an important component of the apparatus, which ensures a significant reduction in the cost of the manufacturing process compared to other chopper and multiple knife ring cutters (messerringzero cutters) used. Such arbor cutters can provide a particle board with a proportion of crushed wood of 30% to 100%. Additionally, the manufacturing method is more cost effective because the arbor cutters can use small diameter wood, peeled or unpeeled, having a diameter less than 0.08 m. The proportion of small diameter wood in the new particle board may be at least 30%, preferably at least 50%.

A trommel 2 is provided as another important equipment unit in the manufacture of particle boards. The use of roller screens is significantly more energy efficient than, for example, disc screens. The trommel is able to sort the generated wood chips directly into fines 12, useful material 11 and optionally coarse material 13 to be sorted. The useful materials include wood chips used in particle board manufacture. The wood chips can be separated again into wood chips for the intermediate layer of the particle board and wood chips for the cover layer. In some cases, it is also possible, for example, to mix fines into the cover layer, in order to make the surface particularly smooth.

At least a part of the useful material 11 is preheated in the hot air separator 3 and at the same time cleaned of coarse material before said material is led into the tumble dryer. In the flow diagrams, more equipment components may generally be arranged between the various stations of importance to the invention. For example, a silo or a storage, an air treatment plant or similar plant unit is not shown.

The wood chips are then dried in one or more commercially available dryers 4, for example for specific sizes or dispersion layers, respectively. The bulk material is then fed from a silo or a storage to a gluing device 5, which is also known. Typically, wood chips are sprayed with a binder in a feed chute or large mixing drum to provide a strong bond during the subsequent pressing process.

The wood chips are separated into different sizes for the individual layers and fed to the individual spreading heads of the spreading station 6, which spread the material evenly distributed over the spreading belt and thus form the bulk material mats 9. The bulk material mat is then introduced into a continuous press 7 where it is pressed under pressure and at an elevated temperature. Such a continuous press is sold by the applicant under the name ContiRoll.

Since the arbor cutting machine produces very thin wood chips (thickness between 0.1 and 0.8 mm) instead of as narrow wood chips as in the case of the knife ring cutting machine, with this method it is possible to achieve bending strength corresponding to the value of EN300 by suitable gluing and pressing as well.

List of reference numerals

1 arbor cutting machine

2 drum screen

3 heat air separator

4 drier

5 gluing device

6 spreading station comprising a spreading head

7 continuous press

8 small diameter wood

9 bulk material pad

10. Shaving board

11. Material for use in articles

12. Fine material

13. Coarse material

Claims

1. A process for manufacturing oriented strand board or wafer board from wood chips having a length of 1 to 60mm, the process comprising the steps of,

a) Pulverizing wood into fine material (12), a useful material (11) and coarse material (13), wherein the useful material has at least a major part of wood chips,

c) At least the materials used for the production are dried,

d) At least a portion of the useful material is glued,

e) At least the material is dispersed into a bulk material pad (9) and

f) Pressing the bulk material mat into oriented strand board or waffle board (10),

it is characterized in that the method comprises the steps of,

the wood used comprises small diameter wood (8) having a diameter of less than 0.08m and at least one arbor cutter (1) is used for the comminution.

2. A method according to claim 1, characterized in that the proportion of wood chips made of small diameter wood (8) in the oriented strand board or waffle board (10) is at least 30%, preferably at least 50%.

3. A method according to claim 1 or 2, characterized in that unpeeled wood is also used as wood.

4. A method according to any one of claims 1 to 3, characterized in that the arbor cutting machine (1) produces wood chips having a thickness of 0.1 to 0.8 mm.

5. The method according to claim 4, characterized in that the thin wood chips in the oriented strand board or waffle board (10) ensure a bending strength corresponding to the value of EN300 by means of a manufacturing process, wherein the standard EN300 defines mechanical properties and relative humidity resistance.

6. Method according to one of claims 1 to 5, characterized in that the sorting is performed at least partly with a trommel (2) or a star screen.

7. Method according to one of claims 1 to 6, characterized in that the sorting is performed before drying (4).

8. A method according to any one of claims 1 to 7, characterized in that the sorting with a trommel (2) or star screen comprises the removal of coarse material (13).

9. A method according to any one of claims 1 to 8, characterized in that the coarse material (13) is separated before gluing.

10. A method according to any one of claims 1 to 9, characterized in that at least a part of the fines (12) is used as a cover layer additive.

11. A method according to any one of claims 1 to 10, characterized in that wood chips for the cover and intermediate layers of oriented strand board or waffle board (10) are fed to individual silos and subsequently glue is applied individually.

12. A method according to any one of claims 1 to 11, characterized in that the wood chips are passed through a hot air separator (3) before being dried.

13. A method according to any one of claims 1 to 11, characterized in that the bark parts remaining in the wood chips are separated during the spreading so that they are spread in the middle area as seen in the thickness of the oriented strand board or waffle board (10).

14. Apparatus for manufacturing oriented strand board or wafer board according to the method according to one of claims 1 to 13, comprising at least one arbor cutter (1), a trommel (2), a dryer (4) for wood chips, a gluing device (5) for wood chips, a spreading station (6) and a continuous press (7).

15. An apparatus according to claim 14, characterized in that the apparatus also comprises a hot air separator (3).

16. Oriented strand board or wafer board manufactured according to one of claims 1 to 13.